1. Field of the Invention
The present invention relates to novel compounds having β2 adrenergic receptor agonist and muscarinic receptor antagonist activity. This invention also relates to pharmaceutical compositions comprising such compounds, processes and intermediates for preparing such compounds and methods of using such compounds to treat pulmonary disorders.
2. State of the Art
Pulmonary disorders, such as asthma and chronic obstructive pulmonary disease (COPD), are commonly treated with bronchodilators. One class of bronchodilator in widespread use consists of β2 adrenergic receptor (adrenoceptor) agonists, such as albuterol, formoterol and salmeterol. These compounds are generally administered by inhalation. Another class of bronchodilator consists of muscarinic receptor antagonists (anticholinergic compounds), such as ipratropium and tiotropium. These compounds are also typically administered by inhalation.
Pharmaceutical compositions containing both a β2 adrenergic receptor agonist and a muscarinic receptor antagonist are also known in the art for use in treating pulmonary disorders. For example, U.S. Pat. No. 6,433,027 discloses medicament compositions containing a muscarinic receptor antagonist, such as tiotropium bromide, and a β2 adrenergic receptor agonist, such as formoterol fumarate.
Although compounds having either β2 adrenergic receptor agonist or muscarinic receptor antagonist activity are known, no compound having both β2 adrenergic receptor agonist and muscarinic receptor antagonist activity has been previously disclosed. Compounds possessing both β2 adrenergic receptor agonist and muscarinic receptor antagonist activity are highly desirable since such bifunctional compounds would provide bronchodilation through two independent modes of action while having single molecule pharmacokinetics. Moreover, a single bifunctional compound would be simpler to formulate for therapeutic uses compared to two separate compounds and would be easier to co-formulate with other therapeutic agents to create triple therapy combinations.